Double Olympic medallist PV Sindhu made yet another first-round exit but Lakshya Sen staved off a spirited challenge from fellow-Indian Priyanshu Rajawat to progress to the second round of the Japan Open Super 750 badminton tournament here on Wednesday.

Newly-crowned Korea Open champions Satwiksairaj Rankireddy and Chirag Shetty also made a good start to their campaign, extending their unbeaten run to 11 matches, following the wins in Yeosu and Indonesia.

Sindhu, who is going through a tough phase of her career, lost 12-21, 13-21 to Zhang Yi Man of China in her opener which lasted 32 minutes. It was her seventh first-round exit in 13 BWF World Tour events this year.

Canada Open champion Sen, returning to action after skipping the Korea event, survived a scare against compatriot Rajawat, prevailing 21-15, 12-21, 24-22 in a 65-minute battle. Sen will face Kanta Tsuneyama of Japan in the second round.

Sindhu, the 2019 world champion, has looked a pale shadow of her past self after her injury rehabilitation and has dropped to world No. 17 after a series of first round exits.

While Sindhu has been struggling, the doubles duo of Satwik and Chirag beat the Indonesian pair of Leo Rolly Carnando and Daniel Marthin 21-16, 11-21, 21-13 to advance.